Was it in black and white? If so, it may be Night Owl. This review doesn't mention it, but I'm almost certain there's a pointless scene of either Leguizamo or the guy who plays the vampire cutting his hair. I haven't seen this is a long time, though.

Pi (dir. by Darren Aronofsky)...also in black and white.There´s a scene where he cut his hair looking at the mirror. He walks by the city and there are some scenes where he is alone...but the city is not abandoned at all.(Movie feels a little industrial?film like Eraserhead). I don´t remember about the sunglasses at night..i can update on that later,since i have it in a Requiem for a Dream double feature dvd.